Wireless charging alignment method and apparatus, wireless charging system, and electric vehicle

ABSTRACT

The technology of this disclosure relates to a wireless charging alignment method and apparatus, a wireless charging system, and an electric vehicle, and belongs to the field of wireless charging. In the wireless charging alignment apparatus, a first detection circuit may detect a first induction signal of a power receive coil in a positioning magnetic field generated by a power transmit coil; a second detection circuit may detect a second induction signal of a location detection coil in the positioning magnetic field; and a location determining circuit may determine a location of the power receive coil relative to the power transmit coil based on the first induction signal and the second induction signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2020/070395, filed on Jan. 6, 2020, which claims priority toChinese Patent Application No. 201910314533.X, filed on Apr. 18, 2019.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the wireless charging field, and inparticular, to a wireless charging alignment method and apparatus, awireless charging system, and an electric vehicle.

BACKGROUND

Wireless charging (WPT) is a technology in which electric energy istransmitted by using a coupling electromagnetic field as a medium, tocharge an in-vehicle power supply of an electric vehicle. Compared withconventional contact charging, the wireless charging has the followingadvantages: easy to use, no spark, no electric shock risk, no mechanicalwear, adaptable to a plurality of severe environments and weather,automatic charging and mobile charging, and the like. Therefore, thewireless charging is widely applied.

In a related technology, a wireless charging system generally includes:a power transmit device disposed on the ground or under the ground, anda power receive device disposed at the bottom of an electric vehicle.The power transmit device includes a power transmit coil, and the powerreceive device includes a power receive coil. After a driver drives theelectric vehicle to align the power receive coil with the power transmitcoil, the power transmit coil may transmit power to the power receivecoil in an electric field coupling manner or a magnetic field couplingmanner. In addition, higher alignment precision between the powertransmit coil and the power receive coil indicates higher efficiency ofpower transmission between the two coils and higher charging efficiency.

However, in the related technology, the driver needs to visually measurea relative location of the two coils, and drive the electric vehiclebased on the relative location, to align the two coils. Alignmentprecision in this alignment method is relatively low.

SUMMARY

This application provides a wireless charging alignment method andapparatus, a wireless charging system, and an electric vehicle, toresolve a problem of relatively low alignment precision in an alignmentmethod in a related technology. Technical solutions are as follows:

According to an aspect, this application provides a wireless chargingalignment apparatus, including a power receive coil, a locationdetection coil, a first detection circuit, a second detection circuit,and a location determining circuit. The power receive coil is configuredto exchange power with a power transmit coil of a transmit end throughelectromagnetic mutual inductance. The first detection circuit isconfigured to detect a first induction signal of the power receive coilin a positioning magnetic field generated by the power transmit coil.The second detection circuit is configured to detect a second inductionsignal of the location detection coil in the positioning magnetic field.The location determining circuit is configured to determine a locationof the power receive coil relative to the power transmit coil based onthe first induction signal and the second induction signal.

In the related technology, a driver visually measures a relativelocation of the two coils. In comparison with the related technology, inthis embodiment of this application, both precision and efficiency ofdetermining the relative location based on the induction signals arehigher. Therefore, alignment precision and alignment efficiency of thetwo coils can be effectively improved.

Optionally, the wireless charging alignment apparatus may be applied toa receive end (that is, a power receive device) in a wireless chargingsystem, or may be applied to a transmit end (that is, a power transmitdevice) in a wireless charging system. In addition, in the wirelesscharging system, the transmit end and the receive end may beinterchanged. In other words, the receive end may also charge thetransmit end. When the wireless charging alignment apparatus is appliedto the transmit end, or when the transmit end and the receive end areinterchanged, the power receive coil described above may also bereferred to as a power transmit coil, and the power transmit coil mayalso be referred to as a power receive coil.

Optionally, the location determining circuit may be configured todetermine, as the location of the power receive coil relative to thepower transmit coil based on a correspondence between an offset locationand each of an induction signal of the power receive coil and aninduction signal of the location detection coil, an offset locationcorresponding to the first induction signal and the second inductionsignal.

The relative location of the two coils is determined based on thecorrespondence, to effectively improve efficiency of determining therelative location, thereby further ensuring alignment efficiency.

Optionally, a plurality of signal groups and an offset locationcorresponding to each signal group may be recorded in thecorrespondence. Each signal group may include a signal value of theinduction signal of the power receive coil and a signal value of theinduction signal of the location detection coil. The locationdetermining circuit may be configured to: determine a first differencebetween a signal value of the first induction signal and the signalvalue of the induction signal of the power receive coil in each signalgroup, and a second difference between a signal value of the secondinduction signal and the signal value of the induction signal of thelocation detection coil in each signal group, to obtain the firstdifference and the second difference of each signal group; anddetermine, as the offset location corresponding to the first inductionsignal and the second induction signal, an offset location correspondingto a signal group whose sum of the first difference and the seconddifference is the smallest in the plurality of signal groups.

In other words, after obtaining the first induction signal and thesecond induction signal, the location determining circuit may determine,as the offset location corresponding to the first induction signal andthe second induction signal, an offset location corresponding to asignal group that is in the correspondence and that is closest to thesignal values of the two induction signals, to ensure detectionprecision and reliability. Herein, the signal group and the offsetlocation may be recorded in the correspondence in a form of a table.

Optionally, the location determining circuit may be configured to:determine a coupling coefficient between the power receive coil and thepower transmit coil based on the first induction signal and a current ora voltage of the power transmit coil; and determine the location of thepower receive coil relative to the power transmit coil based on thecoupling coefficient and the second induction signal.

For example, the location determining circuit may determine, as thelocation of the power receive coil relative to the power transmit coilbased on a pre-stored correspondence between the offset location andeach of a coupling coefficient and the induction signal of the locationdetection coil, the offset location corresponding to the currentlydetected coupling coefficient and the second induction signal.

Optionally, the location determining circuit may be configured to:separately preprocess the first induction signal and the secondinduction signal, and determine the location of the power receive coilrelative to the power transmit coil based on the preprocessed firstinduction signal and the preprocessed second induction signal. Thepreprocessing may include at least one of normalization processing andweighting processing.

Because the first induction signal and the second induction signal maybe different physical quantities or amplitudes of signal values of thefirst induction signal and the second induction signal have relativelylarge difference therebetween, the amplitudes of the signal values ofthe induction signals may be relatively close by preprocessing theinduction signals, thereby improving precision and efficiency ofsubsequently determining the relative location based on the inductionsignals.

Optionally, each of the first induction signal, the second inductionsignal, the induction signal of the power receive coil, and theinduction signal of the location detection coil may include at least oneof a current and a voltage. In addition, a type of the first inductionsignal is the same as a type of the induction signal of the powerreceive coil in the correspondence, and a type of the second inductionsignal is the same as a type of the induction signal of the locationdetection coil in the correspondence.

For example, the first induction signal may be a current or a voltage,and the first detection circuit may be configured to detect only onetype of signal (for example, a voltage), to reduce detection costs.Alternatively, the first induction signal may include a current and avoltage, and the first detection circuit may be configured to detectmany types of signals (for example, a current and a voltage), to ensuredetection reliability.

Optionally, the first induction signal includes a current. The apparatusmay further include a resonant element and a first switch. The powerreceive coil is connected to the resonant element to form a resonantcircuit. The first switch is connected in parallel to the resonantcircuit. The first detection circuit is configured to: when the firstswitch is closed, detect a current flowing through the resonant circuit.

Optionally, the resonant element may include: an inductor connected inseries to the power receive coil and a capacitor connected in parallelto the power receive coil. The current may include at least one of aninductance current flowing through the inductor and a capacitor currentflowing through the capacitor.

For example, the first detection circuit may include two currentdetection circuits. One current detection circuit may be configured todetect the inductance current, and the other direction circuit may beconfigured to detect the capacitor current.

Optionally, the first induction signal includes a current. The apparatusfurther includes a second switch. The second switch is connected inparallel to the power receive coil. The first detection circuit isconfigured to: when the second switch is closed, detect a short-circuitcurrent flowing through the power receive coil.

In this embodiment of this application, the current detected by thefirst detection circuit may include at least one of an inductancecurrent, a capacitor current, and a short-circuit current. Because theinductance current, the capacitor current, and the short-circuit currentare relatively easy to detect, and detection precision is relativelyhigh, the at least one of the detected inductance current, the detectedcapacitor current, and the detected short-circuit current is used as thefirst induction signal, thereby ensuring precision of the obtained firstinduction signal.

Optionally, the first induction signal includes a voltage. The apparatusmay further include a third switch. The third switch is connectedbetween the power receive coil and a subsequent circuit of the powerreceive coil. The first detection circuit is configured to: when thethird switch is opened, detect an open-circuit voltage between two endsof the power receive coil.

For example, the first detection circuit may include a voltage detectioncircuit configured to detect the open-circuit voltage. The open-circuitvoltage detected by the voltage detection circuit may be an alternatingcurrent voltage.

According to another aspect, this application provides a wirelesscharging alignment method. The method may be applied to the wirelesscharging alignment apparatus in the foregoing aspect. The method mayinclude: detecting a first induction signal of a power receive coil in apositioning magnetic field generated by a power transmit coil; detectinga second induction signal of a location detection coil in thepositioning magnetic field; and determining a location of the powerreceive coil relative to the power transmit coil based on the firstinduction signal and the second induction signal, where the powerreceive coil is configured to exchange power with the transmit coil of atransmit end through electromagnetic mutual inductance.

Optionally, the process of determining a location of the power receivecoil relative to the power transmit coil based on the first inductionsignal and the second induction signal may include:

determining, as the location of the power receive coil relative to thepower transmit coil based on a correspondence between an offset locationand each of the induction signal of the power receive coil and theinduction signal of the location detection coil, an offset locationcorresponding to the first induction signal and the second inductionsignal.

Optionally, a plurality of signal groups and an offset locationcorresponding to each signal group may be recorded in thecorrespondence. Each signal group includes a signal value of theinduction signal of the power receive coil and a signal value of theinduction signal of the location detection coil.

The process of determining, based on a correspondence between an offsetlocation and each of the induction signal of the power receive coil andthe induction signal of the location detection coil, an offset locationcorresponding to the first induction signal and the second inductionsignal may include:

determining a first difference between a signal value of the firstinduction signal and the signal value of the induction signal of thepower receive coil in each signal group, and a second difference betweena signal value of the second induction signal and the signal value ofthe induction signal of the location detection coil in each signalgroup, to obtain the first difference and the second difference of eachsignal group; and determining, as the offset location corresponding tothe first induction signal and the second induction signal, an offsetlocation corresponding to a signal group whose sum of the firstdifference and the second difference is the smallest in the plurality ofsignal groups.

Optionally, the process of determining a location of the power receivecoil relative to the power transmit coil based on the first inductionsignal and the second induction signal may include:

determining a coupling coefficient between the power receive coil andthe power transmit coil based on the first induction signal and acurrent or a voltage of the power transmit coil; and determining thelocation of the power receive coil relative to the power transmit coilbased on the coupling coefficient and the second induction signal.

Optionally, the process of determining a location of the power receivecoil relative to the power transmit coil based on the first inductionsignal and the second induction signal may include:

separately preprocessing the first induction signal and the secondinduction signal, where the preprocessing includes at least one ofnormalization processing and weighting processing; and determining thelocation of the power receive coil relative to the power transmit coilbased on the preprocessed first induction signal and the preprocessedsecond induction signal.

Optionally, the first induction signal includes a current. The powerreceive coil is connected to a resonant element to form a resonantcircuit. The first switch is connected in parallel to the resonantcircuit. The process of detecting a first induction signal of a powerreceive coil in a positioning magnetic field generated by a powertransmit coil may include: controlling the first switch to be closed,and detecting a current flowing through the resonant circuit.

Optionally, the first induction signal includes a current. The powerreceive coil is connected in parallel to a second switch. The process ofdetecting a first induction signal of a power receive coil in apositioning magnetic field generated by a power transmit coil mayinclude: in a first time period, controlling the second switch to beclosed, and detecting a short-circuit current flowing through the powerreceive coil.

The process of detecting a second induction signal of a locationdetection coil in the positioning magnetic field may include: in asecond time period, controlling the second switch to be opened, anddetecting the second induction signal of the location detection coil inthe positioning magnetic field, where the second time period and thefirst time period are two non-overlapping time periods.

After the second switch is closed, the short-circuit current flowingthrough the power receive coil is an alternating current. In this case,a magnetic field generated by the alternating current causesinterference to the second induction signal. Therefore, the firstinduction signal and the second induction signal are respectivelydetected in the first time period and the second time period in a timedivision manner, thereby ensuring accuracy of the detected inductionsignals.

Optionally, the first induction signal includes a voltage. The powerreceive coil may be connected to a subsequent circuit of the powerreceive coil by using a third switch. The process of detecting a firstinduction signal of a power receive coil in a positioning magnetic fieldgenerated by a power transmit coil may include: controlling the thirdswitch to be opened, and detecting an open-circuit voltage between twoends of the power receive coil.

According to still another aspect, this application provides a wirelesscharging system. The wireless charging system includes: a power transmitdevice and a power receive device. At least one of the power transmitdevice and the power receive device includes the wireless chargingalignment apparatus according to the foregoing aspect.

According to further another aspect, this application provides anelectric vehicle. The electric vehicle may include the wireless chargingalignment apparatus according to the foregoing aspect.

According to further another aspect, this application provides alocation determining circuit in a wireless charging alignment apparatus.The location determining circuit may include a memory, a processor, anda computer program that is stored in the memory and that can be run onthe processor. When executing the computer program, the processorimplements the step of determining a location of the power receive coilrelative to the power transmit coil in the wireless charging alignmentmethod according to the foregoing aspect.

According to further another aspect, this application provides acomputer readable storage medium. The computer readable storage mediumstores an instruction. When the instruction stored in the computerreadable storage medium is run on a computer, the computer is enabled toperform the step of determining a location of the power receive coilrelative to the power transmit coil in the wireless charging alignmentmethod according to the foregoing aspect.

According to further another aspect, this application provides acomputer program product including an instruction. When the computerprogram product is run on a computer, the computer is enabled to performthe step of determining a location of the power receive coil relative tothe power transmit coil in the wireless charging alignment methodaccording to the foregoing aspect.

In conclusion, the embodiments of this application provide the wirelesscharging alignment method and apparatus, the wireless charging system,and the electric vehicle. The location determining circuit in theapparatus may determine the location of the power receive coil relativeto the power transmit coil based on the induction signals detected bythe detection circuit. In this way, at least one of the receive end andthe transmit end can adjust its location based on the relative location,so that the two coils are aligned. In the related technology, a drivervisually measures a relative location of the two coils. In comparisonwith the related technology, in this embodiment of this application,both precision and efficiency of determining the relative location basedon the induction signals are higher. Therefore, alignment precision andalignment efficiency of the two coils can be effectively improved. Inaddition, because the apparatus can detect the second induction signalof the location detection coil by using the second detection circuit,and can also detect the first induction signal of the power receive coilby using the first detection circuit, precision of the relative locationdetermined by the location determining circuit based on the two types ofinduction signals is higher, thereby effectively ensuring alignmentprecision of the two coils.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an example architectural diagram of a wireless charging systemaccording to an embodiment of this application;

FIG. 2 is an example architectural diagram of another wireless chargingsystem according to an embodiment of this application;

FIG. 3 is an example schematic structural diagram of a wireless chargingalignment apparatus according to an embodiment of this application;

FIG. 4 is an example schematic diagram of a location of a power receivecoil relative to a power transmit coil according to an embodiment ofthis application;

FIG. 5 is an example partial circuit diagram of a wireless chargingalignment apparatus according to an embodiment of this application;

FIG. 6 is an example partial circuit diagram of another wirelesscharging alignment apparatus according to an embodiment of thisapplication;

FIG. 7 is an example partial circuit diagram of still another wirelesscharging alignment apparatus according to an embodiment of thisapplication;

FIG. 8 is an example partial circuit diagram of further another wirelesscharging alignment apparatus according to an embodiment of thisapplication;

FIG. 9 is an example partial circuit diagram of further another wirelesscharging alignment apparatus according to an embodiment of thisapplication;

FIG. 10 is an example circuit diagram of a wireless charging alignmentapparatus according to an embodiment of this application;

FIG. 11 is an example circuit diagram of another wireless chargingalignment apparatus according to an embodiment of this application;

FIG. 12 is an example circuit diagram of still another wireless chargingalignment apparatus according to an embodiment of this application;

FIG. 13 is an example flowchart of a wireless charging alignment methodaccording to an embodiment of this application; and

FIG. 14 is an example schematic structural diagram of a locationdetermining circuit in a wireless charging alignment apparatus accordingto an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following describes in detail a wireless charging alignment methodand apparatus, an electric vehicle, and a wireless charging systemaccording to the embodiments of this application with reference to theaccompany drawings.

FIG. 1 is an architectural diagram of a wireless charging systemaccording to an embodiment of this application. Referring to FIG. 1, thewireless charging system may include a power receive device 10 (e.g., areceive end) and a power transmit device 20 (e.g., a transmit end). Thepower receive device 10 may be disposed in a to-be-charged device. Theto-be-charged device may be an electricity-driven device such as anelectric vehicle or an electric robot. For example, the to-be-chargeddevice shown in FIG. 1 is an electric vehicle, and the power receivedevice 10 is integrated at the bottom of the electric vehicle. The powertransmit device 20 may be disposed in an area such as a wirelesscharging station, a wireless charging parking space, or a wirelesscharging road; and the power transmit device 20 may be disposed on theground, or may be buried under the ground (FIG. 1 shows a case in whichthe power transmit device 20 is buried under the ground). The powerreceive device 10 may be connected to a power supply of theto-be-charged device, and the power transmit device 20 may be connectedto a power supply. When the to-be-charged device enters a wirelesscharging range of the power transmit device 20, the power supply maycharge the power supply of the to-be-charged device by using the powertransmit device 20 and the power receive device 10.

Optionally, the power receive device 10 and the power transmit device 20may exchange power in an electromagnetic induction manner. In addition,the power supply and the power supply of the to-be-charged device mayfurther implement bidirectional charging by using the power receivedevice 10 and the power transmit device 20. To be specific, the powersupply may charge the power supply of the to-be-charged device by usingthe power transmit device 20 and the power receive device 10, or thepower supply of the to-be-charged device may discharge to the powersupply by using the power transmit device 20 and the power receivedevice 10.

FIG. 2 is an architectural diagram of another wireless charging systemaccording to an embodiment of this application. Referring to FIG. 2, thepower transmit device 20 may include a power transmit coil 201, atransmission conversion module 202, a transmission control module 203, atransmission communications module 204, an authentication managementmodule 205, and a storage module 206.

The power transmit coil 201 and a resonant element that mainly includesan inductor and a capacitor can form a resonant circuit. The powertransmit coil 201 is configured to convert a high-frequency alternatingcurrent into a resonant voltage or a resonant current by using theresonant circuit.

The transmission conversion module 202 is separately connected to apower supply 30 and the power transmit coil 201, and is configured to:convert an alternating current or a direct current provided by the powersupply 30 into a high-frequency alternating current, and provide thehigh-frequency alternating current to the power transmit coil 201. Ifthe power supply 30 provides a direct current, the transmissionconversion module 202 may include an inverter circuit and a voltageconversion circuit. If the power supply 30 provides an alternatingcurrent, the transmission conversion module 202 may include a powerfactor correction circuit and an inverter circuit.

The inverter circuit may be integrated with the power transmit coil 201,or may be disposed independently. The power factor correction circuitcan be used to ensure that an input current phase of the wirelesscharging system is consistent with a power grid voltage phase, to reducesystem harmonic content and increase a power factor value, therebyreducing pollution from the wireless charging system to a power grid andimproving reliability. The power factor correction circuit may furtherincrease or reduce an output voltage of the power factor correctioncircuit based on a subsequent requirement. The inverter circuit mayconvert, into a high-frequency alternating current voltage, the voltageoutput by the power factor correction circuit, and apply thehigh-frequency alternating current voltage to the power transmit coil.The high-frequency alternating current voltage can greatly improvetransmission efficiency and a power transmission distance of the powertransmit coil 201.

It should be noted that the power supply 30 may be an external powersupply of the power transmit device 20, or may be a power supplydisposed inside the power transmit device 20. This is not limited inthis embodiment of this application.

The transmission control module 203 is connected to the transmissionconversion module 202, and is configured to control parameters such as avoltage, a current, and a frequency of the transmission conversionmodule 202 based on an actual transmit power requirement for wirelesscharging, to adjust a voltage or a current of the high-frequencyalternating current in the power transmit coil 201.

The transmission communications module 204 is configured to performwireless communication with a power receive device 10. Communicationcontent may include power control information, fault protectioninformation, power-on/off information, interactive authenticationinformation, and the like. For example, the transmission communicationsmodule 204 may receive information such as attribute information, acharging request, and interactive authentication information that are ofthe to-be-charged device and that are sent by the power receive device10. The transmission communications module 204 may further sendinformation such as wireless charging transmission control information,interactive authentication information, and wireless charging historicaldata information to the power receive device 10.

Specifically, a manner of wireless communication between thetransmission communications module 204 and the power receive device 10may include any one of or any combination of Bluetooth, wirelessfidelity (Wi-Fi), ZigBee, radio frequency identification (RFID),long-range (Lora) wireless, and near field communication (NFC).Optionally, the transmission communications module 204 may furthercommunicate with an intelligent terminal of a user to which theto-be-charged device belongs, and the user to which the to-be-chargeddevice belongs may implement remote authentication and user informationtransmission by using a communication function.

The authentication management module 205 may be configured to performinteractive authentication and permission management with theto-be-charged device.

The storage module 206 may be configured to store charging process data,interactive authentication data (for example, interactive authenticationinformation), and permission management data (for example, permissionmanagement information) of the power transmit device 10. The interactiveauthentication data and the permission management data may be set fromthe factory or may be set by the user. This is not limited in thisembodiment of this application.

Still referring to FIG. 2, the power receive device 10 may include apower receive coil 101, a receiving conversion module 102, a receivingcontrol module 103, and a receiving communications module 104.

The power receive coil 101 is configured to receive active power andreactive power transmitted by the power transmit device 20. A couplingmanner of the power transmit coil 201 and the power receive coil 101 inthe wireless charging system may be any selective combination. Forexample, a coupling manner of the two coils may include: S-S coupling,P-P coupling, S-P coupling, P-S coupling, LCL-LCL coupling, LCL-Pcoupling, or the like. Herein, S represents in series, P represents inparallel, L represents an inductor, and C represents a capacitor. TheS-S coupling means that a resonant circuit in the power transmit device20 is series resonance, and a resonant circuit in the power receivedevice 10 is series resonance. The S-P coupling means that a resonantcircuit in the power transmit device 20 is series resonance, and aresonant circuit in the power receive device 10 is parallel resonance.The LCL-LCL type means that a resonant circuit in each of the powertransmit device 20 and the power receive device 10 is an LCL resonantcircuit (that is, a resonant circuit including two inductors L and onecapacitor C).

In addition, to implement a bidirectional charging function of thewireless charging system, each of the power transmit device 20 and thepower receive device 10 may include both a power receive coil and apower transmit coil. The power transmit coil and the power receive coilin each device may be separately disposed, or may be disposed in anintegrated manner.

The receiving conversion module 102 may be connected to an energystorage module 50 by using an energy storage management module 40. Thereceiving conversion module 102 is configured to convert ahigh-frequency resonant current (or a voltage) received by the powerreceive coil 101 into a direct current (or a direct current voltage)required by the energy storage module 50 for charging. The receivingconversion module 102 may include a rectifier circuit and a directcurrent conversion unit. The rectifier circuit may convert thehigh-frequency resonant current (or a voltage) received by the powerreceive coil 101 into a direct current (or a direct current voltage).The direct current conversion unit may provide the direct current (orthe direct current voltage) for a subsequent charging circuit, toimplement charging in a constant mode. The rectifier circuit may beintegrated with the power receive coil 101, or may be disposedindependently.

It should be noted that the energy storage management module 40 and theenergy storage module 50 may be located outside the power receive device10, for example, may be integrated into the power supply of theto-be-charged device. Alternatively, the energy storage managementmodule 40 and the energy storage module 50 may be located inside thepower receive device 10. Referring to FIG. 2, it may be learned that theenergy storage module 50 may be further connected to a drive apparatus60 and is configured to supply power to the drive apparatus 60, to drivethe to-be-charged device.

The receiving control module 103 is configured to control parameterssuch as a voltage, a current, and a frequency of the receivingconversion module 102 based on an actual receive power requirement forwireless charging.

The receiving communications module 104 is configured to communicatewith the transmission communications module 204 in the power transmitdevice 20. A function of the receiving communications module 104corresponds to a function of the transmission communications module 204.

An embodiment of this application provides a wireless charging alignmentapparatus. The apparatus may be applied to the wireless charging systemshown in FIG. 1 or FIG. 2. The wireless charging alignment apparatus maybe disposed in at least one of the power receive device 10 and the powertransmit device 20. Alternatively, the wireless charging alignmentapparatus may be the power receive device 10 or the power transmitdevice 20. For example, the wireless charging alignment apparatus may bethe power receive device 10 disposed in the electric vehicle.

The following provides description by using an example in which thewireless charging alignment apparatus is disposed in the power receivedevice 10 and the power transmit coil is disposed in the power transmitdevice 20. Referring to FIG. 3, the wireless charging alignmentapparatus may include a power receive coil 01, a location detection coil02, a first detection circuit 03, a second detection circuit 04, and alocation determining circuit 05.

The power receive coil 01 is configured to exchange power with the powertransmit coil through electromagnetic mutual inductance.

The first detection circuit 03 may be configured to detect a firstinduction signal of the power receive coil 01 in a positioning magneticfield generated by the power transmit coil, and the second detectioncircuit 04 may be configured to detect a second induction signal of thelocation detection coil 02 in the positioning magnetic field. The powertransmit coil may be a power induction coil specifically used forwireless charging in the power transmit device 20. Alternatively, thepower transmit coil may be a coil specifically used to generate amagnetic field in the power transmit device 20, and may be disposedadjacent to the power induction coil specifically used for wirelesscharging.

The location determining circuit 05 is configured to determine alocation of the power receive coil 01 relative to the power transmitcoil based on the first induction signal and the second inductionsignal.

In this embodiment of this application, after the location determiningcircuit 05 determines the location of the power receive coil 01 relativeto the power transmit coil, at least one of the power receive device 10and the power transmit device 20 may adjust its location based on thelocation, so that the power receive coil 01 can be accurately alignedwith the power transmit coil, to ensure wireless charging efficiency.For example, the power receive device 10 may adjust the location of thepower receive device 10, so that the two coils are aligned.

Optionally, the location of the power receive coil 01 relative to thepower transmit coil may be represented by using the followingcoordinates: coordinates of a central point of the power receive coil 01in a coordinate system in which a central point of the power transmitcoil is used as an origin; or coordinates of a central point of thepower transmit coil in a coordinate system in which a central point ofthe power receive coil 01 is used as an origin. That the power receivecoil 01 is aligned with the power transmit coil may indicate that adistance between the central points of the two coils is less than adistance threshold. The distance threshold may be configured before thedelivery of the power receive device 10 or the power transmit device 20,or may be set by a user. This is not limited in this embodiment of thisapplication.

For example, it is assumed that the wireless charging alignmentapparatus is the power receive device 10 in the electric vehicle. Inthis case, after the location determining circuit 05 determines thelocation of the power receive coil 01 relative to the power transmitcoil, the relative location may be displayed on an in-vehicle displaydevice, so that a driver adjusts a location of the electric vehiclebased on the relative location to align the power receive coil with thepower transmit coil. Alternatively, the location determining circuit 05may directly send the relative location to a controller of the electricvehicle, and the controller of the electric vehicle may automaticallyadjust a location of the electric vehicle based on the relative locationto align the power receive coil with the power transmit coil.

In conclusion, this embodiment of this application provides the wirelesscharging alignment apparatus. The location determining circuit in theapparatus may determine the location of the power receive coil relativeto the power transmit coil based on the induction signals detected bythe detection circuit. In this way, at least one of the power receivedevice and the power transmit device can adjust its location based onthe relative location, so that the two coils are aligned. In the relatedtechnology, a driver visually measures a relative location of the twocoils. In comparison with the related technology, in this embodiment ofthis application, both precision and efficiency of determining therelative location based on the induction signals are higher. Therefore,alignment precision and alignment efficiency of the two coils can beeffectively improved. In addition, because the apparatus can detect thesecond induction signal of the location detection coil by using thesecond detection circuit, and can also detect the first induction signalof the power receive coil by using the first detection circuit,precision of the relative location determined by the locationdetermining circuit based on the two types of induction signals ishigher, thereby effectively ensuring the alignment precision of the twocoils.

In this embodiment of this application, if the wireless chargingalignment apparatus is disposed in the power receive device 10 or is thepower receive device 10, the first detection circuit 03, the seconddetection circuit 04, and the location determining circuit 05 may all becircuits in the receiving control module 103 in the power receive device10. If the wireless charging alignment apparatus is disposed in thepower transmit device 20 or is the power transmit device 20, the firstdetection circuit 03, the second detection circuit 04, and the locationdetermining circuit 05 may all be circuits in the transmission controlmodule 203 in the power transmit device 20.

Optionally, the wireless charging alignment apparatus may furtherinclude a magnetic core. Both the power receive coil 01 and the locationdetection coil 02 may be disposed on the magnetic core, and may be bothlocated on one side of the magnetic core close to the power transmitcoil 01. For example, if the wireless charging alignment apparatus is apower receive device disposed in an electric vehicle, and the powertransmit device is disposed on the ground or buried under the ground,both the power receive coil 01 and the location detection coil 02 may bedisposed on one side of the magnetic core close to the ground.

Because the magnetic core has a relatively high magnetic permeabilityand has a function of aggregating a magnetic field, it can be ensuredthat the induction signals generated by the power receive coil 01 andthe location detection coil 02 in the positioning magnetic field havehigher strength for detection of the induction signals.

Referring to FIG. 3, it may be further learned that, to ensure detectionprecision, the wireless charging alignment apparatus may include aplurality of location detection coils 02 and a plurality of seconddetection circuits 04 in a one-to-one correspondence with the pluralityof location detection coils 02. Each second detection circuit 04 isconnected to a corresponding location detection coil 02, and isconfigured to detect an induction signal of the location detection coil02 that is connected to the second detection circuit 04 and that is inthe positioning magnetic field generated by the power transmit coil.

In this embodiment of this application, a quantity of location detectioncoils 02 disposed in the wireless charging alignment apparatus may begreater than or equal to 3. For example, in the structure shown in FIG.3, four location detection coils 02 are disposed in the wirelesscharging alignment apparatus.

Optionally, a size of each location detection coil 02 may be less than asize of the power receive coil 01. The plurality of location detectioncoils 02 may be evenly distributed, and may be all located in an areaenclosed by the power receive coil 01 or located around the powerreceive coil 01. When the coil is circular, a size of the coil mayindicate a radius or a diameter of the coil. When the coil is polygonal,a size of the coil may indicate a radius or a diameter of a minimumcircumcircle of the coil.

In this embodiment of this application, the location determining circuit05 or a memory connected to the location determining circuit 05 maystore a correspondence between an offset location and each of theinduction signal of the power receive coil 01 and the induction signalof the location detection coil 02. After obtaining the first inductionsignal and the second induction signal, the location determining circuit05 may determine, as the location of the power receive coil 01 relativeto the power transmit coil, an offset location corresponding to thefirst induction signal and the second induction signal in thecorrespondence.

The offset location may be represented by using the followingcoordinates: coordinates of a central point of the power receive coil 01in a coordinate system in which a central point of the power transmitcoil is used as an origin; or coordinates of a central point of thepower transmit coil in a coordinate system in which a central point ofthe power receive coil 01 is used as an origin.

The relative location of the two coils is determined based on thecorrespondence, to effectively improve efficiency of determining therelative location, thereby further ensuring alignment efficiency of thetwo coils.

Optionally, a correspondence between an offset location and each of theinduction signal of the power receive coil 01 and the induction signalof the location detection coil 02 may be obtained through apre-experiment. The experiment process may be: controlling the powertransmit coil driven by an alternating current with a constant root meansquare, to generate the positioning magnetic field; then, graduallymoving the power receive coil 01 and the location detection coil 02, ormoving the power transmit coil, so that the relative location of thepower receive coil 01 and the power transmit coil changes constantly,that is, the offset location of the power receive coil 01 and the powertransmit coil changes constantly; and at each offset location,separately detecting the induction signal of the power receive coil 01in the positioning magnetic field and the induction signal of thelocation detection coil 02 in the positioning magnetic field, to obtainthe correspondence between the offset location and each of the inductionsignal of the power receive coil 01 and the induction signal of thelocation detection coil 02.

To ensure alignment precision, in the process of moving the coils, theoffset location of the power receive coil 01 and the location detectioncoil 02 may be enabled to cover location points in an effectivedetection range as many as possible, so that induction signals of thepower receive coil 01 and the location detection coil 02 at the locationpoints can be obtained. The effective detection range may be a range inwhich at least one of the power receive coil 01 and the locationdetection coil 02 can sense the positioning magnetic field generated bythe power transmit coil.

Referring to FIG. 4, it is assumed that the wireless charging alignmentapparatus includes four location detection coils 02 in total: a locationdetection coil 1 to a location detection coil 4, and coordinates of anoffset location are coordinates of a central point O′ of a power receivecoil 01 in a coordinate system in which a central point O of a powertransmit coil 00 is used as an origin. In addition, to simplifycalculation, the coordinates may be simplified as two-dimensionalcoordinates that are of orthographic projection of the central point O′in a plane in which the power transmit coil 00 is located and that arein a two-dimensional coordinate system (for example, an XOY coordinatesystem shown in FIG. 4) of the plane.

In an experiment process, the power receive coil 01 and the fourlocation detection coils 02 may be controlled to be gradually moved. Ifthe coordinates that are of the orthographic projection of the centralpoint O′ of the power receive coil 01 and that are in the XOY coordinatesystem are (x1, y1), a signal value (for example, a current value of aninductance current) of a detected induction signal of the power receivecoil 01 in a positioning magnetic field is Is1, and signal values (forexample, voltage values of open-circuit voltages) of induction signalsof the four location detection coils 02 in the positioning magneticfield are respectively Ua11, Ua21, Ua31, and Ua41. In this case, it maybe determined that the signal value of the induction signal that is ofthe power receive coil and that corresponds to the offset location (x1,y1) is Is1, and the signal values of the induction signals that are ofthe location detection coils and that corresponds to the offset location(x1, y1) are Ua11, Ua21, Ua31, and Ua41.

Based on the foregoing method, the power receive coil 01 and the fourlocation detection coils 02 are moved. In this way, after the centralpoint O′ of the power receive coil 01 traverses coordinate points in aneffective detection range in the XOY coordinate system, a correspondencebetween the offset location and each of the induction signal of thepower receive coil 01 and the induction signal of the location detectioncoil 02 may be obtained.

The coordinate points in the effective detection range may be allcoordinate points determined within the effective detection range in theXOY coordinate system by using a first length as a unit length of thex-axis and using a second length as a unit length of the y-axis. Thefirst length and the second length may be equal or unequal, and may beset according to a requirement for alignment precision. For example,when a relatively high requirement is imposed on the alignmentprecision, the first length and the second length may be set to berelatively short; or when a relatively low requirement is imposed on thealignment precision, the first length and the second length may be setto be relatively long.

Optionally, in the correspondence obtained based on the foregoingexperiment data, a plurality of signal groups and an offset locationcorresponding to each signal group may be recorded. Each signal groupmay include a signal value of an induction signal of the power receivecoil 01 and a signal value of an induction signal of the locationdetection coil 02.

For example, the finally obtained correspondence may be shown inTable 1. Table 1 shows n (n is an integer greater than 1) signal groupsand an offset location corresponding to each signal group. Each signalgroup includes a signal value of an induction signal of the powerreceive coil 01 and signal values of induction signals of the locationdetection coils 02. It is assumed that a signal value that is of a firstinduction signal and that is obtained by a location determining circuit05 in an actual alignment process is Is2, and signal values that are ofsecond induction signals and that are obtained by the locationdetermining circuit 05 in the actual alignment process are respectivelyUa12, Ua22, Ua32, and Ua42. In this case, according to thecorrespondence shown in Table 1, the location determining circuit 05 maydetermine that a current location of the power receive coil 01 relativeto the power transmit coil is (x2, y2).

TABLE 1 Signal group Signal Signal Signal Signal Signal value of anvalue of an value of an value of an value of an induction inductioninduction induction induction Offset location signal of a signal of asignal of a signal of a signal of a Coordinate Coordinate locationlocation location location power on the x- on the y- detection detectiondetection detection receive axis axis coil 1 coil 2 coil 3 coil 4 coilx1 y1 Ua11 Ua21 Ua31 Ua41 Is1 x2 y2 Ua12 Ua22 Ua32 Ua42 Is2 x3 y3 Ua13Ua23 Ua33 Ua43 Is3 x4 y4 Ua14 Ua24 Ua34 Ua44 Is4 x5 y5 Ua15 Ua25 Ua35Ua45 Is5 . . . . . . . . . . . . . . . . . . . . . xn yn Ua1n Ua2n Ua3nUa4n Isn

In this embodiment of this application, the correspondence between theoffset location and each of the induction signal of the power receivecoil 01 and the induction signal of the location detection coil 02 maybe recorded in a form of a table such as Table 1, or may be recorded ina form of a function. In other words, function fitting may be performedon the offset location obtained from the experiment, the inductionsignal of the location detection coil 02 at the offset location, and theinduction signal of the power receive coil 01 at the offset location, toobtain a function of a relationship between the offset location and eachof the induction signal of the location detection coil 02 and theinduction signal of the power receive coil 01: (x, y)=f(d, b). Herein,(x, y) represents the offset location, d represents the signal value ofthe induction signal of the location detection coil 02, and b representsthe signal value of the induction signal of the power receive coil 01.After obtaining the first induction signal and the second inductionsignals, the location determining circuit 05 may apply the signal valuesof the obtained induction signals to the relationship function, toobtain the location of the power receive coil 01 relative to the powertransmit coil.

It should be noted that when the correspondence is recorded in a form ofa table such as Table 1, the signal value of the first induction signaland the signal values of the second induction signals that are obtainedby the location determining circuit 05 may be different from those ofeach signal group recorded in the table. In this case, the locationdetermining circuit 05 may determine an offset location corresponding toa signal group with a smallest difference as the location of the powerreceive coil 01 relative to the power transmit coil.

In other words, the location determining circuit 05 may be configured todetermine a first difference between the signal value of the firstinduction signal and the signal value of the induction signal of thepower receive coil 01 in each signal group, and a second differencebetween the signal value of the second induction signal and the signalvalue of the induction signal of the location detection coil 02 in eachsignal group, to obtain the first difference and the second differenceof each signal group. Then, an offset location corresponding to a signalgroup whose sum of the first difference and the second difference is thesmallest in the plurality of signal groups may be determined as theoffset location corresponding to the first induction signal and thesecond induction signal. Each of the first difference and the seconddifference may be an absolute value.

It is assumed that the signal value that is of the first inductionsignal and that is obtained by the location determining circuit 05 isIsk, and the signal values that are of the second induction signals andthat are obtained by the location determining circuit 05 arerespectively Ua1k, Ua2k, Ua3k, and Ua4k. In this case, the locationdetermining circuit 05 may separately determine a first differencebetween Isk and the signal value of the induction signal of the powerreceive coil 01 in each signal group, and each second difference betweeneach of the signal values of the induction signals of the locationdetection coils 02 in each signal group and each of Ua1k, Ua2k, Ua3k,and Ua4k, to obtain the first difference and the second differences ofeach signal group. It is assumed that a sum of the first difference andthe second differences of an n^(th) signal group: Isn, Ua1n, Ua2n, Ua3n,and Ua4n is the smallest in the signal groups shown in Table 1. The sumΔU of the first difference and the second differences may be representedas: ΔU=|Isk−Isn|+|Ua1k−Ualn|+|Ua2k−Ua2n|+|Ua3k−Ua3n|+|Ua4k−Ua4n|. Inthis case, the location determining circuit 05 may determine that thecurrent location of the power receive coil 01 relative to the powertransmit coil is an offset location (xn, yn) corresponding to the n^(th)signal group.

For example, referring to Table 2, it is assumed that five offsetlocations: (x1, y1) to (x5, y5) and a signal group corresponding to eachoffset location are recorded in a correspondence stored in the locationdetermining circuit 05; and a signal value that is of a first inductionsignal and that is currently obtained by the location determiningcircuit 05 through measurement performed by two detection circuits inreal time is 43, and signal values that are of second induction signalsand that are currently obtained by the location determining circuit 05through measurement performed by the two detection circuits in real timeare respectively 410, 432, 412, and 1345. In this case, according to theforegoing method, the location determining circuit 05 may separatelycalculate a first difference between the signal value of the firstinduction signal and the signal value of the induction signal of thepower receive coil in each signal group in Table 2, and each seconddifference between each of the signal values of the second inductionsignals and each of the signal values of the induction signals of thelocation detection coils in each signal group, to obtain each sum ofeach first difference and each group of second differences of each ofthe five signal groups: 88, 36, 55, 131, and 208. Because a sum: 36 ofthe first difference between the signal value of the first inductionsignal and a signal value of an induction signal in a second signalgroup, and each second difference between each of the signal values ofthe second induction signals and each of signal values of inductionsignals in a second signal group is the smallest, an offset location(x2, y2) corresponding to the second signal group may be determined asthe location of the power receive coil 01 relative to the power transmitcoil.

TABLE 2 Signal group Signal Signal Signal Signal Signal value of anvalue of an value of an value of an value of an induction inductioninduction induction induction Offset location signal of a signal of asignal of a signal of a signal of a Sum of a first Coordinate Coordinatelocation location location location power difference on the x- on the y-detection detection detection detection receive and second axis axiscoil 1 coil 2 coil 3 coil 4 coil differences x1 y1 379 420 399 1372 3888 x2 y2 402 441 408 1357 46 36 x3 y3 423 461 414 1335 44 55 x4 y4 444479 416 1303 47 131 x5 y5 468 500 417 1276 51 208 Detected induction 410432 412 1345 43 \ signal

In this embodiment of this application, the signal value of theinduction signal of the location detection coil 02 shown in Table 2 maybe a value obtained after sampling processing is performed on a voltageof the location detection coil 02, and the signal value of the inductionsignal of the power receive coil 01 may be a value obtained aftersampling processing is performed on a current of the power receive coil01.

In a scenario in which the four location detection coils 02 are disposedin the wireless charging alignment apparatus, based on an experimentresult, it is indicated that an error in determining the relativelocation based on only the second induction signals of the four locationdetection coils is 63.6% greater than an error in determining therelative location based on both the first induction signal and thesecond induction signals. It can be learned that the alignment methodprovided in this embodiment of this application can be used toeffectively improve alignment precision.

It should be further noted that, in an experiment process of obtainingthe correspondence and in an actual alignment process, the positioningmagnetic field generated by the power transmit coil is generated anddriven by an alternating current with a constant root mean square. Inother words, in the experiment process and in the actual alignmentprocess, the root mean square of the alternating current in the powertransmit coil is fixed.

Optionally, in this embodiment of this application, after obtaining thefirst induction signal and the second induction signal, the locationdetermining circuit 05 may further determine a coupling coefficientbetween the power receive coil 01 and the power transmit coil based onthe first induction signal and a current or a voltage of the powertransmit coil. Then, the location determining circuit 05 determines thelocation of the power receive coil 01 relative to the power transmitcoil based on the coupling coefficient and the second induction signal.

The coupling coefficient may be a coefficient used to reflect a couplingdegree between the power receive coil 01 and the power transmit coil.The current or the voltage of the power transmit coil may be obtainedthrough detection performed by the detection circuit and be sent to thewireless charging alignment apparatus. Alternatively, in the alignmentprocess, the root mean square of the alternating current in the powertransmit coil is the same as the root mean square of the alternatingcurrent in the experiment process. Therefore, the current or the voltageof the power transmit coil may also be a fixed value pre-stored in thelocation determining circuit 05.

For example, when the first induction signal is a short-circuit current,the coupling coefficient k determined based on the current of the powertransmit coil may meet the following:

$k = {\sqrt{\frac{L_{1}}{L_{2}}} \cdot \frac{I_{1}}{I_{2}}}$

Herein, L₁ is an inductance value of the power receive coil 01, L₂ is aninductance value of the power transmit coil, I₁ is a short-circuitcurrent value of the power receive coil 01, and I₂ is a current value ofthe power transmit coil.

When the first induction signal is an open-circuit voltage, the couplingcoefficient k determined based on the current of the power transmit coilmay meet the following:

$k = {\frac{1}{j\;\omega\sqrt{L_{1}L_{2}}} \cdot \frac{U_{S}}{I_{2}}}$

Herein, j is an imaginary unit, ω is an operating frequency of thewireless charging system (that is, a frequency of an alternating currentin the power transmit coil 201), and Us is an open-circuit voltage valueof the power receive coil 01.

When the first induction signal is an open-circuit voltage, the couplingcoefficient k determined based on the voltage of the power transmit coilmay further meet the following:

$k = {\sqrt{\frac{L_{2}}{L_{1}}} \cdot \frac{U_{S}}{U_{P}}}$

Herein, Up is a voltage value of the power transmit coil.

When determining the location of the power receive coil 01 relative tothe power transmit coil based on the coupling coefficient and the secondinduction signal, the location determining circuit 05 may alternativelydetermine the location of the power receive coil 01 relative to thepower transmit coil based on a correspondence that is between the offsetlocation and each of the induction signal of the location detection coiland the coupling coefficient and that is generated in thepre-experiment. For a process of generating the correspondence betweenthe offset location and each of the coupling coefficient and theinduction signal of the location detection coil, refer to the foregoingdescription.

In this embodiment of this application, the first induction signal andthe second induction signal may be different physical quantities or anamplitude difference between signal values of the first induction signaland the second induction signal is relatively large. For example, thefirst induction signal is a current, and the second induction signal isa voltage. To improve processing efficiency and location determiningprecision, after obtaining the first induction signal and the secondinduction signal, the location determining circuit 05 may furtherseparately preprocess the first induction signal and the secondinduction signal, so that amplitudes of the signal value of thepreprocessed first induction signal and the signal value of the secondinduction signal are similar. Then, the location determining circuit 05determines the location of the power receive coil 01 relative to thepower transmit coil based on the preprocessed first induction signal andthe preprocessed second induction signal.

The preprocessing may include at least one of normalization processingand weighting processing. The normalization processing on an inductionsignal may means to normalize a signal value of the induction signal toa value between 0 and 1. The weighting processing on an induction signalmay means to multiply a weighting factor and a signal value of theinduction signal.

For example, it is assumed that when the central point O′ of the powerreceive coil 01 is at an i^(th) coordinate point in the coordinatesystem in which the central point O of the power transmit coil 00 isused as an origin, the signal value of the first induction signalobtained by the location determining circuit 05 is d_(1i). In this case,a signal value d_(1i)′ obtained after the location determining circuit05 performs normalization processing on the signal value d_(1i) of thefirst induction signal may be represented as follows:

d _(1i) ′=d _(1i)−min(D ₁)/max(D ₁)−min(D ₁)

Herein, D₁ represents a set of signal values that are of the firstinduction signals and that are obtained by the location determiningcircuit 05 when the central point O′ of the power receive coil 01 is atdifferent coordinate points, max (D₁) represents a maximum value in theset D1, and min (D₁) represents a minimum value in the set D1. When thesignal values of all the first induction signals in the set D₁ areequal, max (D₁) may be equal to the signal value of the first inductionsignal, and min (D₁) may be 0.

Similarly, it is assumed that when the wireless charging alignmentapparatus includes M location detection coils 02, and when the centralpoint O′ of the power receive coil 01 is at an i^(th) coordinate pointin the coordinate system in which the central point O of the powertransmit coil 00 is used as an origin, a signal value that is of asecond induction signal of an m^(th) location detection coil 02 and thatis obtained by the location determining circuit 05 is b_(mi). In thiscase, a signal value b_(mi)′ obtained after the location determiningcircuit 05 performs normalization processing on the signal value b_(mi)of the second induction signal may be represented as follows:

$b_{mi}^{\prime} = \frac{b_{mi} - {\min\left( B_{m} \right)}}{{\max\left( B_{m} \right)} - {\min\left( B_{m} \right)}}$

Herein, M is an integer greater than 1, m is a positive integer notgreater than M, and B_(m) represents a set of signal values that are ofthe second induction signals of the m^(th) location detection coil 02and that are obtained by the location determining circuit 05 when thecentral point O′ of the power receive coil is at different coordinatepoints.

In this embodiment of this application, signal values of inductionsignals in the set D₁ and the set B_(m) may be obtained duringgenerating the correspondence between the offset location and each ofthe induction signal of the power receive coil 01 and the inductionsignal of the location detection coil 02. In other words, the signalvalues of the induction signals in the set D₁ and the set B_(m) may beobtained by traversing the central point O′ of the power receive coil 01at each coordinate point within the effective detection range anddetecting the induction signal at each coordinate point.

Optionally, the location determining circuit 05 may further prestore aweighting factor of an induction signal of the power receive coil 01 anda weighting factor of an induction signal of each location detectioncoil 02. The weighting factor of each induction signal may be determinedbased on an experiment (that is, the foregoing experiment used togenerate a correspondence). After obtaining the first induction signaland the second induction signal, the location determining circuit 05 maymultiply a signal value of each induction signal and a weighting factorcorresponding to the induction signal, so that amplitudes of signalvalues of induction signals are relatively close.

It is assumed that a weighting factor of an induction signal of thepower receive coil 01 is α₁ and a weighting factor of an inductionsignal of the m^(th) location detection coil 02 in the M locationdetection coils is β_(m). In this case, a signal value d_(1i)″ obtainedafter the location determining circuit 05 performs weighting processingon a signal value d_(1i) of the first induction signal may berepresented as d_(1i)″=α₁·d_(1i); and a signal value b_(1i)″ obtainedafter the location determining circuit 05 performs weighting processingon a signal value b_(mi) of the second induction signal of the m^(th)location detection coil 02 may be represented as b_(1i)″=β_(m)·b_(mi).

It should be noted that in this embodiment of this application, thelocation determining circuit 05 may perform only normalizationprocessing or weighting processing on each induction signal, or thelocation determining circuit 05 may perform both normalizationprocessing and weighting processing on each induction signal, where asequence of performing the normalization processing and the weightingprocessing may be adjusted.

It should be further noted that, if each induction signal is aninduction signal before being preprocessed in the correspondence betweenthe offset location and each of the induction signal of the powerreceive coil 01 and the induction signal of the location detection coil02 that are obtained by the location determining circuit 05, thelocation determining circuit 05 does not need to preprocess the firstinduction signal and the second induction signal when determining theoffset location based on the first induction signal and the secondinduction signal. If each induction signal is the preprocessed inductionsignal in the correspondence between the offset location and each of theinduction signal of the power receive coil 01 and the induction signalof the location detection coil 02 that are obtained by the locationdetermining circuit 05, the location determining circuit 05 needs topreprocess the first induction signal and the second induction signalwhen determining the offset location based on the first induction signaland the second induction signal. In addition, the preprocessing mannerneeds to be the same as the preprocessing manner for the inductionsignal recorded in the correspondence, to ensure detection accuracy.

For example, it is assumed that the preprocessing is weightingprocessing, a weighting factor of the induction signal of the powerreceive coil 01 is 15, and a weighting factor of the induction signal ofeach location detection coil 02 is 1. In this case, a signal value of aninduction signal obtained after the weighting processing is performed ona signal value of an induction signal obtained through real-timemeasurement in each signal group shown in Table 2 may be shown in Table3. Referring to Table 3, it may be learned that the signal value of thepreprocessed first induction signal is 645, and the signal values of thesecond induction signals are the same as those before the preprocessingand are respectively 410, 432, 412, and 1345. Each sum of each firstdifference between the signal value of the preprocessed first inductionsignal and the signal value of the induction signal in each signalgroup, and each second difference between each of the signal values ofthe second induction signals and each of the signal values of theinduction signals in each signal group is 158, 78, 69, 187, or 320.

Because a sum: 69 of a first difference between the signal value of thepreprocessed first induction signal and a signal value of an inductionsignal in a third signal group, and each second difference between eachof the signal values of the second induction signals and each of signalvalues of induction signals in the third signal group is the smallest,an offset location (x3, y3) corresponding to the third signal group maybe determined as the location of the power receive coil 01 relative tothe power transmit coil.

TABLE 3 Signal group Signal Signal Signal Signal Signal value of anvalue of an value of an value of an value of an induction inductioninduction induction induction Offset location signal of a signal of asignal of a signal of a signal of a Sum of a first Coordinate Coordinatelocation location location location power difference on the x- on the y-detection detection detection detection receive and second axis axiscoil 1 coil 2 coil 3 coil 4 coil differences x1 y1 379 420 399 1372 570158 x2 y2 402 441 408 1357 690 78 x3 y3 423 461 414 1335 660 69 x4 y4444 479 416 1303 705 187 x5 y5 468 500 417 1276 765 320 Measuredinduction 410 432 412 1345 645 \ signal

In this embodiment of this application, each of the first inductionsignal, the second induction signal, the induction signal of the powerreceive coil 01, and the induction signal of the location detection coil02 may include at least one of a current and a voltage. In addition, atype of the first induction signal is the same as a type of theinduction signal of the power receive coil 01, and a type of the secondinduction signal is the same as a type of the induction signal of thelocation detection coil 02.

Optionally, the first detection circuit 03 may include a currentdetection circuit. Correspondingly, the first induction signal mayinclude a current. For example, the current may be an alternatingcurrent, and the current detection circuit may be a circuit configuredto detect the alternating current. The current detection circuit mayinclude components such as a current transformer, an amplifier, and ananalog-to-digital converter.

FIG. 5 is a circuit diagram of a wireless charging alignment apparatusaccording to an embodiment of this application. Referring to FIG. 5, theapparatus may further include a resonant element 06 and a first switchS₁. In the circuit diagram, a power receive coil 01 may be equivalent toan inductor L1. The inductor L1 is connected to the resonant element 06to form a resonant circuit, and the first switch S₁ is connected inparallel to the resonant circuit. When the first switch S₁ is closed,the first detection circuit 03 may detect a current flowing through theresonant circuit. In other words, after the resonant circuit isshort-circuited, the first detection circuit 03 may detect the currentflowing through the resonant circuit.

Referring to FIG. 6 and FIG. 7, it may be learned that the resonantelement 06 may include an inductor Lf connected in series to a powerreceive coil 01 (that is, an inductor L1 shown in FIG. 6 and FIG. 7),and a capacitor Cf connected in parallel to the power receive coil 01.

Optionally, as shown in FIG. 6, the first detection circuit 03 may beconnected to the inductor Lf. Correspondingly, the current detected bythe first detection circuit 03 is an inductance current flowing throughthe inductor Lf.

Alternatively, as shown in FIG. 7, the first detection circuit 03 may beconnected to the capacitor Cf. Correspondingly, the current detected bythe first detection circuit 03 is a capacitor current flowing throughthe capacitor Cf.

Optionally, referring to FIG. 8, the apparatus may further include asecond switch S₂. The second switch S₂ is connected in parallel to thepower receive coil 01 (that is, an inductor L1 shown in FIG. 8). Thefirst detection circuit 03 is connected to the power receive coil 01.When the second switch S₂ is closed, that is, after the power receivecoil 01 is short-circuited, the first detection circuit 03 may detect ashort-circuit current flowing through the power receive coil 01.Correspondingly, the current detected by the first detection circuit 03is the short-circuit current flowing through the power receive coil 01.

Alternatively, the first detection circuit 03 may include at least twocurrent detection circuits, and the at least two current detectioncircuits may be separately connected to at least two of the inductor Lf,the capacitor Cf, and the power receive coil 01. Correspondingly, thecurrent detected by the first detection circuit 03 may include at leasttwo of an inductance current, a capacitor current, and a short-circuitcurrent.

Because the inductance current, the capacitor current, and theshort-circuit current are relatively easy to detect, and detectionprecision is relatively high, the at least one of the detectedinductance current, the detected capacitor current, and the detectedshort-circuit current is used as the first induction signal, therebyensuring precision of the obtained first induction signal.

In this embodiment of this application, the first detection circuit 03may further include a voltage detection circuit. Correspondingly, thefirst induction signal may include a voltage. For example, the voltagemay be an alternating current voltage, and the first detection circuit03 may be a voltage detection circuit configured to detect thealternating current voltage. The first detection circuit 03 may includecomponents such as a rectifier circuit, an amplifier, and ananalog-to-digital converter.

As shown in FIG. 9, the apparatus may further include a third switch S₃.The third switch S₃ may be connected between the power receive coil 01(that is, an inductor L1 shown in FIG. 9) and a subsequent circuit (notshown in FIG. 9) of the power receive coil 01. The subsequent circuitmay include a circuit such as a receiving conversion module 102 in apower receive device 10.

The first detection circuit 03 may be connected in parallel to the powerreceive coil 01, and is configured to: when the third switch S₃ isopened, detect an open-circuit voltage between two ends of the powerreceive coil 01.

Optionally, the first detection circuit 03 may include both a currentdetection circuit and a voltage detection circuit. Correspondingly, thefirst induction signal detected by the first detection circuit 03 mayinclude both a current and a voltage. For example, the first inductionsignal may include a short-circuit current of the power receive coil 01and an open-circuit voltage between the two ends of the power receivecoil 01.

If the first detection circuit 03 detects only one type of signal (forexample, one of a capacitor current, an inductance current, ashort-circuit current, and an open-circuit voltage), detection costs canbe reduced. If the first detection circuit 03 can detect a plurality oftypes of signals (for example, at least two of a capacitor current, aninductance current, a short-circuit current, and an open-circuitvoltage), reliability of the detected first induction signal can beensured.

In this embodiment of this application, the second detection circuit 04may include at least one of a voltage detection circuit and a currentdetection circuit. Correspondingly, the second induction signal mayinclude at least one of a voltage and a current. The voltage may includeat least one of a resonant voltage and an open-circuit voltage. Thecurrent may include at least one of a resonant current and ashort-circuit current.

Optionally, the location detection coil 02 may be alternativelyconnected to a resonant element to form a resonant circuit. In thiscase, the resonant voltage may indicate a voltage of the resonantcircuit. The open-circuit voltage may be a voltage between two ends ofthe location detection coil 02 when the location detection coil 02 isdisconnected from the resonant element. The resonant current may be acurrent flowing through the resonant circuit. The short-circuit currentmay be a current flowing through the location detection coil 02 afterthe location detection coil 02 is short-circuited.

For example, the second detection circuit 04 may include a voltagedetection circuit configured to detect an alternating current voltage,and the second detection circuit 04 may include components such as arectifier circuit, an amplifier, and an analog-to-digital converter.

Referring to FIG. 10 to FIG. 12, four location detection coils 02 may bedisposed in a wireless charging alignment apparatus. The four locationdetection coils 02 may be respectively equivalent to an inductor La1, aninductor La2, an inductor La3, and an inductor La4 in a circuit.Correspondingly, four second detection circuits 04 are disposed in thewireless charging alignment apparatus. Each second detection circuit 04may be connected in parallel to one inductor, and be configured to:detect a voltage of the inductor connected to the second detectioncircuit 04, and send the voltage to a location determining circuit 05.

It should be noted that a switch status of each of the first switch S₁,the second switch S₂, and the third switch S₃ may be controlled by thelocation determining circuit 05; or may be controlled by a switchcontrol circuit independent of the location determining circuit 05 inthe wireless charging alignment apparatus.

It should be further noted that if the wireless charging alignmentapparatus is disposed in a power receive device 10 or is a power receivedevice 10, resonant elements such as the inductor Lf and the capacitorCf may be elements in a receiving conversion module 102 in the powerreceive device 10. If the wireless charging alignment apparatus isdisposed in a power transmit device 20 or is a power transmit device 20,resonant elements such as the inductor Lf and the capacitor Cf may beelements in a transmission conversion module 202 in the power transmitdevice 20.

It should be further noted that the wireless charging alignmentapparatus may be applied to a receive end (e.g., a power receive device)in a wireless charging system, or may be applied to a transmit end(e.g., a power transmit device) in a wireless charging system. Inaddition, in the wireless charging system, the transmit end and thereceive end may be interchanged. In other words, the receive end mayalso charge the transmit end. When the wireless charging alignmentapparatus is applied to the transmit end, or when the transmit end andthe receive end are interchanged, the power receive coil described abovemay also be referred to as a power transmit coil, and the power transmitcoil may also be referred to as a power receive coil.

In conclusion, the embodiments of this application provide the wirelesscharging alignment apparatus. The location determining circuit in theapparatus may determine the relative location of the two coils based onthe induction signals detected by the detection circuit. In this way, atleast one of the power receive device and the power transmit device canadjust its location based on the relative location, so that the twocoils are aligned. In the related technology, a driver visually measuresa relative location of the two coils. In comparison with the relatedtechnology, in this embodiment of this application, both precision andefficiency of determining the relative location based on the inductionsignals are higher. Therefore, alignment precision and alignmentefficiency of the two coils can be effectively improved.

In addition, the apparatus can detect the second induction signal of thelocation detection coil by using the second detection circuit, and canalso detect the first induction signal of the power receive coil byusing the first detection circuit. A size and a coverage area of thepower receive coil are both larger than those of the location detectioncoil. The power receive coil has a relatively large difference from thelocation detection coil in terms of features. Therefore, precision ofthe relative location determined by the location determining circuitbased on the two types of induction signals is higher, therebyeffectively ensuring the alignment precision of the two coils. Inaddition, because the power receive coil is an original coil in thewireless charging alignment apparatus, by using the power receive coilfor alignment, hardware usage of the wireless charging alignmentapparatus can be effectively improved, thereby ensuring alignmentprecision and further avoiding increase of costs and a volume of thewireless charging alignment apparatus.

An embodiment of this application further provides a wireless chargingalignment method. The method may be applied to the wireless chargingalignment apparatus provided in the foregoing embodiments. Referring toFIG. 13, the method may include the following steps:

Step 301: Detect a first induction signal of a power receive coil in apositioning magnetic field generated by a power transmit coil.

The power receive coil is configured to exchange power with the transmitcoil of a transmit end through electromagnetic mutual inductance.

For example, it is assumed that a to-be-charged device is an electricvehicle, a power receive coil 01 is disposed in the electric vehicle,and a power transmit coil is disposed in a wireless charging station. Inthis case, when the electric vehicle needs to be wirelessly charged, acentral controller of the electric vehicle may deliver a charginginstruction to a receiving control module 103 in a power receive device10. Because the power transmit coil needs to be first aligned with thepower receive coil before the charging is started in a wireless chargingsystem, the wireless charging system first enters an alignment state. Inthis case, the receiving control module 103 may send, by using areceiving communications module 104, a positioning instruction to atransmission communications module 204 in a power transmit device 20located on the ground. After receiving the positioning instruction byusing the transmission communications module 204, the transmissioncontrol module 203 of the power transmit device 20 may control the powertransmit coil 201 to generate a magnetic field used for locationdetection, that is, the foregoing positioning magnetic field.

After the power transmit coil 201 generates the positioning magneticfield, and after the power receive device 10 enters a range of thepositioning magnetic field with the electric vehicle, the power receivecoil 101 and a location detection coil may generate induction signals.

Step 302: Detect a second induction signal of the location detectioncoil in the positioning magnetic field.

If the wireless charging alignment apparatus includes a plurality oflocation detection coils, a second induction signal of each locationdetection coil in the positioning magnetic field needs to be detected.

Step 303: Determine a location of the power receive coil relative to thepower transmit coil based on the first induction signal and the secondinduction signal.

In this embodiment of this application, step 301 may be implemented by afirst detection circuit 03 in the wireless charging alignment apparatus,step 302 may be implemented by a second detection circuit 04 in thewireless charging alignment apparatus, and step 303 may be implementedby a location determining circuit 05 in the wireless charging alignmentapparatus.

In an optional implementation, step 303 may include:

determining, as the location of the power receive coil relative to thepower transmit coil based on a correspondence between an offset locationand each of an induction signal of the power receive coil and aninduction signal of the location detection coil, an offset locationcorresponding to the first induction signal and the second inductionsignal.

For example, the process of determining, based on the correspondence,the offset location corresponding to the first induction signal and thesecond induction signal in step 303 may include the following steps:

Step S31: Determine a first difference between a signal value of thefirst induction signal and a signal value of the induction signal of thepower receive coil in each signal group, and a second difference betweena signal value of the second induction signal and a signal value of theinduction signal of the location detection coil in each signal group, toobtain the first difference and the second difference of each signalgroup.

Step S32: Determine, as the offset location corresponding to the firstinduction signal and the second induction signal, an offset locationcorresponding to a signal group whose sum of the first difference andthe second difference is the smallest in the plurality of signal groups.

Each of the first difference and the second difference may be anabsolute value. For the process of determining the location of the powerreceive coil relative to the power transmit coil based on thecorrespondence, refer to the foregoing description.

In another optional implementation, step 303 may include:

determining a coupling coefficient between the power receive coil andthe power transmit coil based on the first induction signal and acurrent or a voltage of the power transmit coil; and determining thelocation of the power receive coil relative to the power transmit coilbased on the coupling coefficient and the second induction signal.

For the process of determining the location of the power receive coilrelative to the power transmit coil based on the coupling coefficientand the second induction signal, refer to the foregoing description.

Optionally, step 303 may include: separately preprocessing the firstinduction signal and the second induction signal, where thepreprocessing includes at least one of normalization processing andweighting processing; and determining the location of the power receivecoil relative to the power transmit coil based on the preprocessed firstinduction signal and the preprocessed second induction signal. For theprocess of preprocessing the induction signals, refer to the foregoingdescription.

In this embodiment of this application, the first induction signaldetected by the first detection circuit 03 may include at least one of acurrent and a voltage. The second induction signal detected by thesecond detection circuit 04 may also include at least one of a currentand a voltage.

Optionally, referring to FIG. 5 to FIG. 7, the apparatus may furtherinclude a resonant element 06 and a first switch S₁. The power receivecoil is connected to the resonant element 06 to form a resonant circuit.The first switch S₁ is connected in parallel to the resonant circuit.

Step 301 may include: controlling the first switch S₁ to be closed, anddetecting a current flowing through the resonant circuit. In otherwords, the first induction signal may include the current flowingthrough the resonant circuit.

For example, the resonant element 06 may include a capacitor Cf and aninductor Lf. In this case, the current flowing through the resonantcircuit may include at least one of a capacitor current and aninductance current.

Optionally, referring to FIG. 8, the apparatus may further include asecond switch S₂. The second switch S₂ is connected in parallel to thepower receive coil.

Step 301 may include: in a first time period, controlling the secondswitch S₂ to be closed, and detecting a short-circuit current flowingthrough the power receive coil. In other words, the first inductionsignal may include the short-circuit current flowing through the powerreceive coil.

Step 302 may include: in a second time period, controlling the secondswitch S₂ to be opened, and detecting the second induction signal of thelocation detection coil in the positioning magnetic field.

The second time period and the first time period may be twonon-overlapping time periods. In other words, the short-circuit currentand the second induction signal may be detected in a time divisionmanner. When the second switch S₂ is closed and the power receive coilis short-circuited, the short-circuit current flowing through the powerreceive coil is an alternating current, and a magnetic field generatedby the alternating current causes interference to the second inductionsignal generated by the location detection coil. Therefore, theshort-circuit current and the second induction signal may be detected ina time division manner, to ensure reliability of the detected secondinduction signal.

It should be noted that, after the first switch S₁ is closed, theinductor, the capacitor, and the power receive coil form a resonantcircuit. Because impedance of the inductor and the capacitor relative tothe power receive coil is relatively large, the current flowing throughthe power receive coil is very small, so that no interference is causedto the detection of the second induction signal. Therefore, when thefirst induction signal includes the inductance current or the capacitorcurrent, the detection of the inductance current or the capacitorcurrent may be performed synchronously with the detection of the secondinduction signal.

Optionally, referring to FIG. 9, the apparatus may further include athird switch S₃. The third switch S₃ is separately connected to thepower receive coil and a subsequent circuit of the power receive coil.Correspondingly, step 301 may include: controlling the third switch tobe opened, and detecting an open-circuit voltage between two ends of thepower receive coil. In other words, the first induction signal mayfurther include the open-circuit voltage between the two ends of thepower receive coil.

It should be noted that a sequence of steps of the wireless chargingalignment method provided in this embodiment of this application may beappropriately adjusted, or steps may be correspondingly increased ordecreased based on a situation. For example, step 301 and step 302 maybe performed simultaneously, or step 302 may be performed before step301. Variation or replacement readily figured out by a person skilled inthe art within the technical scope disclosed in the present technologyshall fall within the protection scope of the present technology.

In conclusion, the embodiments of this application provide the wirelesscharging alignment method. According to the method, the relativelocation of the two coils may be determined based on the detectedinduction signals. In this way, at least one of the power receive deviceand the power transmit device can adjust its location based on therelative location, so that the two coils are aligned. In the relatedtechnology, a driver visually measures a relative location of the twocoils. In comparison with the related technology, in this embodiment ofthis application, both precision and efficiency of determining therelative location based on the induction signals are higher. Therefore,alignment precision and alignment efficiency of the two coils can beeffectively improved.

In addition, according to the method, the second induction signal of thelocation detection coil may be detected, and the first induction signalof the power receive coil may be further detected. A size and a coveragearea of the power receive coil are both larger than those of thelocation detection coil. The power receive coil has a relatively largedifference from the location detection coil in terms of features.Therefore, precision of the relative location determined based on thetwo types of induction signals is higher, thereby effectively ensuringthe alignment precision of the two coils.

An embodiment of this application further provides a wireless chargingsystem. Referring to FIG. 1 and FIG. 2, the wireless charging systemincludes a power transmit device 20 and a power receive device 10. Atleast one of the power transmit device 20 and the power receive device10 may include the wireless charging alignment apparatus provided in theforegoing embodiment.

When the wireless charging alignment apparatus is applied to the powertransmit device 20, the power receive coil described above may also bereferred to as a power transmit coil, and the power transmit coil mayalso be referred to as a power receive coil.

An embodiment of this application further provides an electric vehicle.The electric vehicle may include the wireless charging alignmentapparatus provided in the foregoing embodiment. For example, theelectric vehicle may include a power receive device 10, and the powerreceive device 10 includes the wireless charging alignment apparatusprovided in the foregoing embodiment.

It should be understood that the location determining circuit 05 of thewireless charging alignment apparatus in this embodiment of thisapplication may alternatively be implemented by using anapplication-specific integrated circuit (ASIC) or a programmable logicdevice (PLD). The PLD may be a complex program logic device (CPLD), afield-programmable gate array (FPGA), generic array logic (GAL), or anycombination thereof. Optionally, the step of determining the location ofthe power receive coil relative to the power transmit coil in thewireless charging alignment method provided in the foregoing methodembodiment may also be implemented by using software. When this step isimplemented by using software, the circuit (that is, the locationdetermining circuit 05) configured to implement this step in thewireless charging alignment apparatus may be a software module.

FIG. 14 is a schematic structural diagram of a location determiningcircuit in a wireless charging alignment apparatus according to anembodiment of this application. Referring to FIG. 14, the locationdetermining circuit may include a processor 1201, a memory 1202, anetwork interface 1203, and a bus 1204. The bus 1204 is configured toconnect the processor 1201, the memory 1202, and the network interface1203. A communication connection to another device may be implemented byusing the network interface 1203 (which may be wired or wireless). Thememory 1202 stores a computer program 12021, and the computer program12021 is configured to implement various application functions.

It should be understood that in the embodiment of this application, theprocessor 1201 may be a CPU, or the processor 1201 may be anothergeneral purpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field programmablegate array (FPGA), a GPU or another programmable logic device, adiscrete gate or a transistor logic device, a discrete hardwarecomponent, or the like. The general purpose processor may be amicroprocessor, any conventional processor, or the like.

The memory 1202 may be a volatile memory or a nonvolatile memory, or mayinclude both a volatile memory and a nonvolatile memory. The nonvolatilememory may be a read-only memory (ROM), a programmable read-only memory(PROM), an erasable programmable read-only memory (EPROM), anelectrically erasable programmable read-only memory (EEPROM), or a flashmemory. The volatile memory may be a random access memory (RAM), used asan external cache. Through examples but not limitative descriptions,many forms of RAMs may be used, for example, a static random accessmemory (SRAM), a dynamic random access memory (DRAM), a synchronousdynamic random access memory (s SDRAM), a double data rate synchronousdynamic random access memory (DDR SDRAM), an enhanced synchronousdynamic random access memory (ESDRAM), a synchronous link dynamic randomaccess memory (SLDRAM), and a direct rambus dynamic random access memory(DR RAM).

The bus 1204 may further include a power bus, a control bus, a statussignal bus, and the like, in addition to a data bus. However, for cleardescription, various types of buses in the figure are marked as the bus1204.

The processor 1201 is configured to execute the computer program storedin the memory 1202. The processor 1201 executes the computer program12021 to implement the step of determining the location of the powerreceive coil relative to the power transmit coil in the foregoing methodembodiment.

An embodiment of this application further provides a computer readablestorage medium. The computer readable storage medium stores aninstruction. When the computer readable storage medium runs on acomputer, the computer is enabled to perform the step of determining thelocation of the power receive coil relative to the power transmit coilin the foregoing method embodiment.

An embodiment of this application further provides a computer programproduct including an instruction. When the computer program product runson a computer, the computer is enabled to perform the step ofdetermining the location of the power receive coil relative to the powertransmit coil in the foregoing method embodiment.

It should be noted that, in this embodiment of this application, “atleast one” means one or more, and “a plurality of” means two or more.The term “and/or” describes an association relationship betweenassociated objects and represents that at least three relationships mayexist. For example, A and/or B may represent the following three cases:Only A exists, both A and B exist, and only B exists. A and B may be ina singular or plural form. The character “/” generally indicates an “or”relationship between the associated objects.

The foregoing descriptions are merely optional embodiments of thisapplication, but are not intended to limit this application. Anymodification, equivalent replacement, or improvement made withoutdeparting from the spirit and principle of this application shall fallwithin the protection scope of this application.

1. A wireless charging alignment apparatus, comprising: a power receivecoil; a location detection coil; a first detection circuit; a seconddetection circuit; and a location determining circuit, wherein the powerreceive coil is configured to exchange power with a power transmit coilof through electromagnetic mutual inductance; the first detectioncircuit is configured to detect a first induction signal of the powerreceive coil in a positioning magnetic field generated by the powertransmit coil; the second detection circuit is configured to detect asecond induction signal of a location detection coil in the positioningmagnetic field, and the location determining circuit is configured todetermine a location of the power receive coil relative to the powertransmit coil based on the first induction signal and the secondinduction signal.
 2. The wireless charging alignment apparatus accordingto claim 1, wherein the location determining circuit is configured todetermine, as the location of the power receive coil relative to thepower transmit coil based on a correspondence between an offset locationand each of an induction signal of the power receive coil and aninduction signal of the location detection coil, the offset locationcorresponding to the first induction signal and the second inductionsignal.
 3. The wireless charging alignment apparatus according to claim2, wherein a plurality of signal groups and the offset locationcorresponding to each signal group may be recorded, each signal groupcomprises a signal value of the induction signal of the power receivecoil and the signal value of the induction signal of the locationdetection coil, and the location determining circuit is configured to:determine a first difference between the signal value of the firstinduction signal and the signal value of the induction signal of thepower receive coil in each signal group, and a second difference betweenthe signal value of the second induction signal and the signal value ofthe induction signal of the location detection coil in each signalgroup, to obtain the first difference and the second difference of eachsignal group; and determine, as the offset location corresponding to thefirst induction signal and the second induction signal, the offsetlocation corresponding to a signal group whose sum of the firstdifference and the second difference is the smallest in the plurality ofsignal groups.
 4. The wireless charging alignment apparatus according toclaim 2, wherein each of the first induction signal, the secondinduction signal, the induction signal of the power receive coil, andthe induction signal of the location detection coil comprises at leastone of a current and a voltage; and a type of the first induction signalis the same as a type of the induction signal of the power receive coil,and a type of the second induction signal is the same as a type of theinduction signal of the location detection coil.
 5. The wirelesscharging alignment apparatus according to claim 1, wherein the locationdetermining circuit is configured to: determine a coupling coefficientbetween the power receive coil and the power transmit coil based on thefirst induction signal and a current or a voltage of the power transmitcoil; and determine the location of the power receive coil relative tothe power transmit coil based on the coupling coefficient and the secondinduction signal.
 6. The wireless charging alignment apparatus accordingto claim 1, wherein the location determining circuit is configured to:separately preprocess the first induction signal and the secondinduction signal, and determine the location of the power receive coilrelative to the power transmit coil based on the preprocessed firstinduction signal and the preprocessed second induction signal, whereinpreprocessing the first induction signal and the second induction signalcomprises at least one of normalization processing and weightingprocessing.
 7. The wireless charging alignment apparatus according toclaim 1, wherein the first induction signal comprises a current, thewireless charging alignment apparatus further comprises a resonantelement and a first switch, the power receive coil is connected to theresonant element to form a resonant circuit, and the first switch isconnected in parallel to the resonant circuit; and the first detectioncircuit is configured to: when the first switch is closed, detect thecurrent flowing through the resonant circuit.
 8. The wireless chargingalignment apparatus according to claim 7, wherein the resonant elementcomprises: an inductor connected in series to the power receive coil,and a capacitor connected in parallel to the power receive coil; and thecurrent detected by the first detection circuit comprises at least oneof an inductance current flowing through the inductor and a capacitorcurrent flowing through the capacitor.
 9. The wireless chargingalignment apparatus according to claim 1, wherein the first inductionsignal comprises a current, the wireless charging alignment apparatusfurther comprises a first switch, and the first switch is connected inparallel to the power receive coil; and the first detection circuit isconfigured to: when the first switch is closed, detect a short-circuitcurrent flowing through the power receive coil.
 10. The wirelesscharging alignment apparatus according to claim 1, wherein the firstinduction signal comprises a voltage, the apparatus further comprises afirst switch, and the first switch is connected between the powerreceive coil and a subsequent circuit of the power receive coil; and thefirst detection circuit is configured to: when the first switch isopened, detect an open-circuit voltage between two ends of the powerreceive coil.
 11. A wireless charging alignment method, comprising:detecting a first induction signal of a power receive coil in apositioning magnetic field generated by a power transmit coil; detectinga second induction signal of a location detection coil in thepositioning magnetic field; and determining a location of the powerreceive coil relative to the power transmit coil based on the firstinduction signal and the second induction signal, wherein the powerreceive coil is configured to exchange power with a power transmit coilthrough electromagnetic mutual inductance.
 12. The method according toclaim 11, wherein determining the location of the power receive coilrelative to the power transmit coil comprises: determining, as thelocation of the power receive coil relative to the power transmit coilbased on a correspondence between an offset location and each of aninduction signal of the power receive coil and an induction signal ofthe location detection coil, the offset location corresponding to thefirst induction signal and the second induction signal.
 13. The methodaccording to claim 12, wherein a plurality of signal groups and theoffset location corresponding to each signal group may be recorded, eachsignal group comprises a signal value of the induction signal of thepower receive coil and the signal value of the induction signal of thelocation detection coil; and determining the offset locationcorresponding to the first induction signal and the second inductionsignal comprises: determining a first difference between the signalvalue of the first induction signal and the signal value of theinduction signal of the power receive coil in each signal group, and asecond difference between the signal value of the second inductionsignal and the signal value of the induction signal of the locationdetection coil in each signal group, to obtain the first difference andthe second difference of each signal group; and determining, as theoffset location corresponding to the first induction signal and thesecond induction signal, the offset location corresponding to a signalgroup whose sum of the first difference and the second difference is thesmallest in the plurality of signal groups.
 14. The method according toclaim 11, wherein determining the location of the power receive coilrelative to the power transmit coil based on the first induction signaland the second induction signal comprises: determining a couplingcoefficient between the power receive coil and the power transmit coilbased on the first induction signal and a current or a voltage of thepower transmit coil; and determining the location of the power receivecoil relative to the power transmit coil based on the couplingcoefficient and the second induction signal.
 15. The method according toclaim 11, wherein determining the location of the power receive coilrelative to the power transmit coil based on the first induction signaland the second induction signal comprises: separately preprocessing thefirst induction signal and the second induction signal, whereinpreprocessing the first induction signal and the second induction signalcomprises at least one of normalization processing and weightingprocessing; and determining the location of the power receive coilrelative to the power transmit coil based on the preprocessed firstinduction signal and the preprocessed second induction signal.
 16. Themethod according to claim 11, wherein the first induction signalcomprises a current, the power receive coil is connected to a resonantelement to form a resonant circuit, and the resonant circuit isconnected in parallel to a first switch; and detecting the firstinduction signal of the power receive coil comprises: controlling thefirst switch to be closed, and detecting the current flowing through theresonant circuit.
 17. The method according to claim 11, wherein thefirst induction signal comprises a current, and the power receive coilis connected in parallel to a first switch; detecting the firstinduction signal of the power receive coil comprises: in a first timeperiod, controlling the first switch to be closed, and detecting ashort-circuit current flowing through the power receive coil; anddetecting the second induction signal of the location detection coilcomprises: in a second time period, controlling the first switch to beopened, and detecting the second induction signal of the locationdetection coil in the positioning magnetic field, wherein the secondtime period and the first time period are two non-overlapping timeperiods.
 18. The method according to claim 11, wherein the firstinduction signal comprises a voltage, and the power receive coil isconnected to a subsequent circuit of the power receive coil by using afirst switch; and detecting the first induction signal of the powerreceive coil comprises: controlling the first switch to be opened, anddetecting an open-circuit voltage between two ends of the power receivecoil.
 19. A wireless charging system, comprising: a power transmitdevice; and a power receive device, wherein at least one of the powertransmit device and the power receive device includes a wirelesscharging alignment apparatus, wherein the wireless charging alignmentapparatus comprises: a power receive coil, a location detection coil, afirst detection circuit, a second detection circuit, and a locationdetermining circuit, wherein the power receive coil is configured toexchange power with a power transmit coil through electromagnetic mutualinductance; the first detection circuit is configured to detect a firstinduction signal of the power receive coil in a positioning magneticfield generated by the power transmit coil; the second detection circuitis configured to detect a second induction signal of a locationdetection coil in the positioning magnetic field; and the locationdetermining circuit is configured to determine a location of the powerreceive coil relative to the power transmit coil based on the firstinduction signal and the second induction signal.
 20. An electricvehicle, comprising: a wireless charging alignment apparatus, whereinthe wireless charging alignment apparatus comprises: a power receivecoil, a location detection coil, a first detection circuit, a seconddetection circuit, and a location determining circuit, wherein the powerreceive coil is configured to exchange power with a power transmit coilthrough electromagnetic mutual inductance; the first detection circuitis configured to detect a first induction signal of the power receivecoil in a positioning magnetic field generated by the power transmitcoil; the second detection circuit is configured to detect a secondinduction signal of a location detection coil in the positioningmagnetic field; and the location determining circuit is configured todetermine a location of the power receive coil relative to the powertransmit coil based on the first induction signal and the secondinduction signal.